Potted plant watering system. (Involves water pumps.)

No not yet.

I am trying (yeah, right) to keep it simple.

Basically there will be a pump; 5 (unless I get more pots) solenoids; a vent valve and a rain sensor.
Oh, sorry: And an LED.

Sensors? You mean for the rain detection? No not yet. Don't know how to detect rain electronically yet.